CompositeForm::__clone

public function __clone()
{
	$forms = [];
	foreach ($this->nestedForms as $key => $form)
	{
		if (is_array($form))
		{
			foreach ($form as $formKey => $item)
			{
				$forms[$key][$formKey] = clone $item;
			}
		}
		else
		{
			$forms[$key] = clone $form;
		}
	}
	$this->nestedForms = $forms;
}